Suction cleaner



June 9, 1953 w. H. WOESSNER 2,641,333

SUCTION CLEANER Filed April 18, 1951 s Sheet-Sheet 1 IN VEN TOR.

WILLIAM H. WOESSNER ATT'Y June 9, 1953 w. H. WOESSNER 2,641,333

\ SUCTION CLEANER Filed April 18, 1951 6 Sheets-Sheet 2 mmvrom WILLIAMH. WOESSNER June 9, 1953 w. H. WOESSNER 2,641,333

SUCTION CLEANER Filed April 18, 1951 e Shets-Sheet 3 IN V EN TOR.

I LL-IAM H.WOESSNER ATT'Y June 9, 1953 w. H. WOESSNER 2,641,333

SUCTION CLEANER Filed April 18, 1951 6 Sheets-Sheet 4 mmvrox; WILLIAM H,WOESSNER ATT'Y June 9, 1953 w. H-. WOESSNER SUCTION CLEANER 6Sheets-Sheet 5 Filed April 18, 1951 INVENTOR. WILLIAM H. WOESSNER @WATT'Y' June 9, 1953 w. H. WOESSNER 2,641,333

SUCTION CLEANER filed April 18, 1951 6 Sheets-Sheet 6 INVENTOR. NILLIAMH.WOESSNER ATT'Y Patented June 9, 1953.

SUGTION CLEANER.:.

WillianrIL Woessnen, Canton, .0hio,.. assignor. to The..Hoover Company,NorthCanton, ()hio a...

corporation of' Ohio ApplitatiomAprihlS, 1951;. ,SeriaLIENOt. 221,366

241Cl'aims; (GL.183.--51)f The" present invention relates; to:suctioncleans eessand more particularly;- to va filter. bagltherefor; and.to'themethod of :making: the same.

Specifically; the; inventionrelates to. inexpen-v siyegzporouspaperfilter. bags which are-intended to be discarded and replaced by new:onesiafter becoming soiled by zuseo Thepfilter bags, of; thepresent=.invention:are=;for-. attachment to (the .exhausts-nozzle; ofan,upright type,- cleaner; and arecintendeditozbe protected by an air;pervious cloth. bag which does not act: as. a filterebut merely-permits.passage ;.of-. clean air; filtered" by the encased porous paper 1'filter bags.

The porous paper bag .to:whichthe-dnvention relates; whenexpandedtis:QfJarge diameter/oyer tlrea maj orportiorriof itsslength'to: providea large filtering; area; At;its; ;lower-. end,;howe.ver; itmust-,fitt; closely: about: the: exhaust 1 nozzle of l a suction:cleaner: which; hasa; comparatively smaller diameter:

For r that: reason the bagrzisaproyided with in; wardly extending:accordion: like: f older. or: pleats over its entire length'and; maybe'formediin a well"kncwmbag:making-machine: The-diameter ot the openlowerropen.end ofztheabagzwithycers tain folds turned? inwardly and:sealed, is sub; stantially the same as thatioffthesexhaust nozzle of thecleanera to which it 1151130: bezzattached.

The-lower open endi'of the porous paper-shag must be clamped to'the'exhausttnozzleof, fa suc.=.= ti'on cleaner; and' inorder' to preventfailure when expanded, the lower folded-endfofthe bag: should bereenforced and properly positionedperiphorally.

It* is also necessary to' provide-some means; for preventing-dustanddirtwhich is blown upwards ly intothe bag and separated "fromtherair; from falling backwardl'y' into the exhaust nozzle: ofthe-"cleaner.-

It is' knownin the art to attach the lower end ofa rigid tubeto theinner lowenopenen'd-"of the bag' neckand extend the tube-upwardly intothe bag to form a trap aboutits periph'eryvas the" bag is expanded byair pressure during use.

Difii'culty has been experienced in attaching both'thereenforcement andthe dirttrapr tube to the foldedlower end of the bagon .account ofthefolds in the bag;

Prior to' the present invention it was; usual practice to sew or stitchboth the-reinforcement'and the dirt'trap to'thefolded lower endof thebag which required separatelyholding'both oftliese items duringthe-sewing operation and sewing across the folds of the bag asthe seamwas" made about the "periphery of the folded-and 2. narrowed end thereofwhile thereenforcement and a dirt .trap were. held, in, place on .the.inner and :outer sides of thefolded .open bagsendn According to thepresent: invention the; re: enforcementand .dirt traparemade of a,single blanlc of acomparatively stiifipaper, impregnated with a cementwhich. may be thermosetting so that both the reenforcement'andthedirtl-trap maypbev. appliedto the lower folded open. end ofthehpaper. bag by: aosimplel operation.

The blank is cut and scored'to form the proper panels, flaps andltabs.The. blank iathen folded along, longitudinalscoring; lines. and. thefree edgessecuredtogether to. form. a..double\ layer sleeve. whichmay,be expanded. into" a, circle by pressing inwardly. on .the... edges.-thereof.

The flat lend whicheventually. forms .the dirt trap, is inserted intothe flat open endliofl the pprouspaper bag insideopposedfolds with alocatingnotch formed in. the reenforcement'and positioned; at the edgeof. the material. of the open end,of .'the..bag.. Thevarious flaps andtabs aresthen .fdldedibackwardly over the outside of thefolded open endof-the bag,,two of the flaps or tabs bfeing folded inwardly from the.outside. to overlap. the interior, of..the\ folds resulting in aconstruction .-.in. which. theupper and lower folds of the bag are.permanently. sealedagainst .unfolding movement. while. the centralfoldsvare free to ibeuexpandedrto form. a circular, neck .of, adiameter; tol fitztheexhaust nozzle of. theolaner.

The open end.of.the-.bag and. they combined reenforcement, and... dirttrap iscrthenlexpanded andtelescopedtoverlalheated.form of substantial-1y the-same diameteras the. exhaust nczzleof theccleaner. Heatingshoesare ,then applied over theexterior. periphery of. theassembly toheat sealthematerial ofthereenforcement andtrap to .the. interior andexterior. of the bag neck, it being v noted that .the.,material ofthereenforcementsis. sealed... interiorly, and exteriorlyof. certainafolds:of .thebag andextend across .the fold"; ed edges thereof so astolocktheunoccupied folds againstexpansion at the lowerlopenendof the. bag and.thus formabag. neck which whenv expanded is of; substantially thesame.diameter. as that. of theexhaustnozzle to whichit is. tobeapplied andwhich may be easily telescoped over, the exhaust nozzle .with a.positioningv notch. mating with a complementary detent'on theexhaustnozzle. H

The patentto Smellie- 2,418,371; dated=April 1; 1947', proposedto=eliminate the necessity of separately sewing the dirt trap and;reenforcings'memberx-to. the mouth' of "the-bag. However, accordi'ngstothe teaching-of that patent .itisnem 3 essary to separately secure theunoccupied folds to each other prior to the application of the dirt trapand then to separately secure the dirt trap and reenforcement to the bagmouth.

The present invention is an improvement over the Smellie construction inthat it eliminates the necessity of separately securing the unoccupiedfolds to each other while retaining the function of the separatesecuring means.

Other objects and advantages of the present invention will becomeapparent as the description proceeds when taken in connection with theaccompanying drawings in which:

Figure l is a view of the blank of one form of the combined neckreenforcement and dirt trap of the present invention, the heavy singlelines denoting cuts through the material and the light double linesdenoting score or fold lines;

Figure 2 shows the blank of Fig. 1 applied to the open end of the filterbag preparatory to the 'heat sealing operation;

Fig. 5 is a perspective view of the invention of Fig. 1 in the finalstages of the folding operation;

Figure 6 is a perspective view of a preferable heat sealing apparatus asthe dirt valve and positioning reenforcement is being heat sealed;

Figure '7 shows the second modification folded preparatory to the heatsealing operation; and

Figure 8 shows the blank for the second modification.

Referring to the drawings, the porous filter bag is generally indicatedby the reference numeral l0. It is formed by a bag forming machine in amanner well known in the art and is adapted to be enclosed in aprotecting pervious cloth bag as disclosed in the United States patentto Smellie 2,418,371, dated April 1, 1947.

As shown in Fig. 4 the bag I0 is folded so as to have on each side threeoutwardly extending reentrant or accordion-like folds H, l2 and I3 and.two inwardly extending reentrant or accordion-like folds 4 and I5extending the full length thereof. The open end of the bag I0 is cut ina shallow V-shape as shown at |6.

The reenforcing and valve element comprises a valve portion I1 and areenforcing portion 8. The blank of the first modification is shown inFig. 1. The reenforcing portion |8 comprises a central reenforcingextension !9, side reenforcing extensions 20, intermediate flaps 2|,connecting tabs 22 and locking tabs 23. The valve portion I! comprises acentral panel 24 and side panels 25 and 26. The side panel 25 isprovided with an extension 21 shown separated therefrom by a dash lineas shown in Fig. 1.

The extension l9 and panel 24 are connected .by a fold line. 28 and attheir central junction are secured to panels 25 and 26'by fold lines 4as shown. The panels 25 and 26 are connected to panel 24 by fold lines36.

The blank of Fig. 1 is stamped from the rolls or sheets of paperpreferably impregnated with a heat scalable cement of any suitablecharacter.

Assembly of the modification of Figs. 1 to 5, inc.

The blank of Fig. 1 is manually manipulated and the panels 25 and 26folded over the panel 24, about fold lines 36, with the extension 21 ofpanel 25 overlapping the free edge of panel 26. If desired, theextension 21 may be sealed to the panel 26 in any suitable manner. Thetabs 22 and 23 and flaps 2| are spread outwardly as shown in Fig. 4which leaves the spaces 31 in the top edge of the panel 24, whichopenings were formerly occupied by the locking tabs 23.

The folds of the open end of the bag Ill are then separated as shown inFig. 4 and theflat valve or dirt trap portion inserted so as to occupy aposition between mating folds, preferably the middle folds l2. Theinsertion is continued until the edge of the opening 29 is located atthe apex of the V-shaped end I6 of bag M as shown in Fig. 2.

The open end of the bag ID is then collapsed and the extensions 20turned rearwardly and underneath over the ends of folds l3 and I5 sothat the edges of extensions 20 will overlap, as shown in dotted lines38 of Fig. 2, to leave the flaps 2| and the tabs 22 and 23 extendingsidewardly from the edges of the bag 0. That will lock the folds l3 andI5 together.

The flaps 2| are then turned toward each other along lines 30 across theedges of the bag It] to overlap folds l2 and I3 with the flaps 2| lyingover the material of the upper side of bag l0 above the openings 3'! inthe panel 24 so as to reenforce the bag mouth at those'points. The tabs22 will form a continuation of extensions 20 and will lie on theopposite side of the bag mouth from the flaps 2|.

The locking tabs 23 are then turned inwardly across the edge of thefolds of the bag mouth and will occupy the openings 31 which theyoriginally occupied as shown in Fig. 3. The extension I9 is then turnedbackwardly over the V- shape end l6 of the bag mouth. The locking tabs23 and the extension I9 lock the folds II and I4 while the junctionbetween the flap 2| and tab 22 also look the folds l2 and |3 across theedges of the bag I0.

The material of the flaps, extensions, tabsand panels, positioned asabove described, are then heat-sealed to the material of the bag mouthboth inside and outside in any suitable manner, but preferably by theapparatus shown in Fig. 6. The heat sealing operation will permanentlylock the folds of the bag together, permanently attach the dirt trap I!to the inside of the bag mouth and reenforce the bag mouth both insideand outside.

The bag mouth is then ready for application to an exhaust nozzle of asuction cleaner similar to that shown in the United States patent toWhite 2,295,981, dated September 15, 1942. The notch formed by theopening 29 corresponds to the notch shown in the White patent.

The mechanism of the apparatus of Fig. 6 is mounted on a suitablesupport 50. A mandrel '5| projects forwardly from the support and issurrounded by four heating shoes 52 innerleaved ,at 53 so as to form acomplete annulus when in closed position. The heating shoes arereciprotending apex.

form a continuation of lines 66 and 69.

the folds l3 and i5 of the bag.

.cated inwardly and outwardly by'air cylinders 54 controlled by asuitable valve mechanism operated in any suitable manner.

The mandrel 5| and the shoes 52 are heate by electric heaters toapproximately 250 F. and

controlled by a timer which applies heat'for approximately 11 seconds.The timer may also "control the valve mechanism for reciprocating theshoes 52.

In operation the mouth'of the bag is expanded as shown in Fig. 3, itsopen end slidover the on both the inside and outside.

In the modification of Figs. 7 and 8 thecom- 'bined valve andreenforcement comprises a valve portion 56 and a reenforcing portion 6|.The valve portion 60 comprises a central panel 62 and side panels 63connected to the central panel 62 by fold lines 64. Centralreenforcing'extensions 65 and 66 are separated from each other by a outline 6'. and are attached to the central panel 62 by diagonal fold lines68 and 69 respectively, which meet substantially centrally of thecentral panel 62 to form an outwardly ex-- Side reenforcing flaps Illare connected to the side panels 63 by fold lines H which Circularopenings 12 are formed in the blank on the meeting line H adjacent theedges of side panels 63 and side flaps M as shown in Fig. 8.

A suitable glue or cement which may be'pressure sensitive, heat scalableor of any other kind is applied to one face of the material'of the blank3 above the dot-dash line 73 of Fig. 8'. The material of the blank maybe impregnated with a heat scalable cement as in the first modification.

Assembly ofFz'gs. 7 and 8 The side panel 63 is folded over on top of thepanels 62 along the fold lines 64 so as to overlap as shown at M of Fig.7. If desired, the overlapping portions M may be glued or cemented toeach other in any suitable manner.

The mouth of the bag ill is then opened as shown in Fig. 4 and the valveportion '50 inserted between mating folds, preferably the central foldsl2, until the edge of the openings 12 "mates with the V-shaped edge 56of the bag mouth as shown in Fig. 7. The central extensions'65 and 66are then folded backwardly and downwardly over the bag mouth so as tooverlap as shown at of Fig. '7. which will lock The side extensions 70are then turned backwardly and upwardly over the edge of the bag mouthso as to "overlap as shown at T6 in Fig. '7, it being noted that theopenings 12 will mate to form a semicircular notch in the edge of thebag mouth. The side flaps 10 will thus lock the upperfolds H and M.

The glue or cement may then be activated in any suitable manner. If itis heat scalable the machine of Fig. 6 may be used as previouslydescribed. If the cement is pressure sensitive pressure may be appliedeither by the machine of Fig. 6 without using heat or in any othersuitable manner.

According to both modifications, both the upper folds II and M and thelower folds l3 and i5 are permanently sealed to each other leaving thefolds I2 free to expand to form the bag mouth and that, without the useof sepa- 6 rate means'ifor securing the unoccupiedfolds to- Eether.

While I have shown and described "but two modifications of myinventionitis to be understood that those modifications are to be taken asillustrative only and not in a limiting sense. I do not wish to belimited to the particular structure or method shown and described but toinclude all equivalent variations thereof except as limited by the scopeof theclaims.

I claim:

L'The method of making a filter bag comprising the steps of, stamping ablank from" paper impregnated with a heat scalable cement, said blankbeing straight at one end and having reenforcing extensions connected toits other end by fold lines, folding saidblank into the form of a flatsleeve with reenforcing extensions extending from each flat sidethereof, inserting the straight end of said sleeve between opposed foldsof a tube of filter material having accordionlike folds extendinginwardly from its opposed sides and two unfolded sides with the edges ofsaid sleeve lying between the apices of the opposed folds, folding saidreenforcing extensions across the ends of said folds to lie against theopposed unfolded'siclcs of said tube and applyingheat to the innersurface of'said sleeve and'to the outer surface of said extensions tobond said sleeve to the inner surface of said folds and to bond saidextension to the outer surface of the unfolded sides of said tube.

2. The method of making a filter bag comprising: forming an open endedtube of filter material folded along its opposite sides to form a pairof central opposed outwardly extending reentrant folds,'and a pair offlat unfolded sides which cooperate with said central folds to formpairs of outer opposed outwardly extendingreentrant folds with theapices of said folds extending along the edges of the unfolded sides andith the walls of said folds on each edge of said tube superimposed uponeach other and upon the unfolded sides; forming a flat sleeve havingintegral extensions formed on both sides at one end;

inserting the free end of said sleeve into said central opposed foldswith its edges positioned within the apices thereof; folding saidextensions across the ends of said folds to lie against the 'unfoldedsides of said tube and securing said sleeve to the walls of said centralfolds and said extensions to the unfolded sides of said tube.

'3. The method of making a filter bag comprising, forming a flat openended folded tube of filtering material folded along its opposed sidesto form a plurality of opposed outwardly extending reentrant folds andopposed unfolded sides with the aplces'of said folds extending along theedges of the unfolded sides'and with the walls of said foldssuperimposedupon each other and upon the unfolded-sides at each edge of said tube,cutting said folds and the unfolded sides at the open end of saidtube toform a shallow reentrant V-shapcd end, forming a flatten d tubularsleeve having integral extensions on both sides anda locating notchformed centrally on its one side at one end of said sleeve, insertingthe unextended end of said sleeve into one'pair of said opposed foldswith its edges lying within-the apices of said folds and the inner edgeof said'locating'notch positioned at the apex of the shallow reentrantv-shaped end of the tube, folding said extensions across the ends ofsaid folds to lie against the unfolded sides of said tube and securingsaidextensions to saidunfolded sides and said sleeve -to 'thewalls ofthefolds m which it ls-positioned.

4. The method of making a filter bag compris ing, forming an open endedtube from filtering material, folding said tube along two of its opposedsides to form a plurality of opposed outwardly extending reentrant foldsand opposed unfolded flat sides with the outer apices of said foldsextending along the edges of the unfolded sides and with the walls ofsaid folds superimposed upon each other and upon the unfolded sides ofsaid tube at each edge thereof, forming a flattened sleeve havingintegral extensions on each side at one end inserting the unextended endof said sleeve into one pair of said opposed folds with its edges lyingwithin the apices of said folds, folding said extensions over the endsof said folds to lie against the outer surface of the unfolded sides ofsaid tube at its open end, bonding said sleeve to the inner surface ofthe folds in which it is positioned and bonding said extensions to theouter surface of the unfolded sides of said tube.

5. The method of making a filter bag comprising, folding an open endedtube of filtering material along two of its opposed sides to form aplurality of mating outward extending accordion-like folds and opposedflat unfolded sides with the outer apices of said folds extending alongthe outer edges of the unfolded sides and with the walls of said tubesuperimposed upon each other and upon the unfolded sides of said tube ateach edge thereof, forming a flattened mouth and dirt trap formingsleeve from paper impregnated with a heat scalable cement, said sleevehaving integral extensions on each side at one end thereof, insertingthe unextended end of said sleeve into one pair of said opposed foldswith its edges positioned within the apices of said folds, folding saidextensions over the end of said folds to lie against the outer surfaceof the unfolded sides of said tube and applying heat to the innersurface of said sleeve and to the outer surface of said extensions toheat seal them to the open end of said folded tube.

6. The method of making a filter bag comprising: forming a blank from asheet of paper im;- pregnated with a heat sealable cement and having adirt trap and bag mouth forming portion and a reenforcing portion; saidtrap forming portion including a central panel and a side panel hingedto each side edge of said central panel; said reenforcing portionincluding a central extension hinged to said central panel, a sideextension hinged to each of said side panels on a diagonal fold linesloping toward said central panel, a flap hinged to the inner edge ofeach of said side extensions by a diagonal fold line and a locking tabhinged to the lower side of each of said flaps by fold lines forming acontinuation of the fold lines for said side extensions and being cutfrom the material of said central panel; folding said side panels oversaid central panel so that their edges overlap; bonding the overlappingedges to each other; inserting said folded trap forming portion into thecentral fold of a flattened open end filter bag having accordionlikefolds in its opposed edges; folding said central extension across theends of said folds to lie against one of the unfolded sides of the bag;folding said side extensions across the ends of said folds to lieagainst the other unfolded side of said bag; folding said flaps acrossthe folded edges of the bag to lie against the first unfolded side ofthe bag on either side of said central extension; folding said lockingtabs across the ends of said 'fold to lie against the interior ofthe-centralfold of the bag and applying heat to bond said panels.extensions, flaps and tabs to the surface of the bag where they contacttherewith.

7. The method of making a filter bag comprising; forming a blank from asheet of paper having a dirt trap forming portion and a reenforcingportion; said trap forming portion including a central panel and a sidepanel hinged toeach side edge thereof; said reenforcing portionincludinga side extension hinged to one end of each of said panels on a diagonalfold line sloping away from said central panel, a pair of centralextensions hinged to said central panel on fold lines forming extensionsof the fold lines of said side extensions, said central extensions beingseparated by a out line extending diagonally sideward from the junctionof their fold lines; folding said side panels over on said central panelso that their edges overlap; bonding said overlapping edges to eachother; inserting the folded trap forming portion into the central foldsof a flattened open ended filter bag having accordion-like folds in eachof the opposite edges thereof; folding said central extensions acrossthe ends of the folds to lie against one unfolded side of said bag;folding said side extensions across the ends of the folds to lie againstthe other unfolded side of the bag and bonding said panels andextensions to the surface of the bag where they contact therewith.

8. In a suction cleaner, an open ended filter bag folded along two ofits opposed sides to form a plurality of opposed mating outwardlyextending accordion-like folds and opposed flat unfolded sides with theouter apices of said folds extending along the edges of the unfoldedsides and the walls of said folds being superposed upon each other andupon the walls forming the unfolded sides of said bag at each edgethereof, the material of said folds and flat sides being cut to form ashallow reentrant V-shaped open end for said bag, a flattened mouthforming sleeve positioned within one pair of said opposed I folds withits edges extending to the outer apices of said folds, integralextensions on each side of said sleeve, said extensions being foldedacross stantially at the apex of the V-shaped open end of said bag, saidsleeve and extension be- .ing impregnated with a heat scalable cement,said sleeve being heat sealed to the inner sides ,of the folds in whichit is positioned and said extensions being heat sealed to the outersurfaces of the unfolded sides of said bag.

9. In a suction cleaner, an open ended filter bag foldedalong oppositesides to form a plurality'of opposed pairs of outwardly extendingreentrant folds and opposed fiatunfolded sides with the outer apices ofsaid folds extending along the edges of said flat sides with the wallsof said folds being superposed on each other and upon the walls formingsaid flat sides at each edge of said bag, a flattened tubular sleevepositioned between the walls of one pair of said opposed reentrant foldswith its edges extending to the apices thereof, extensions integral witheach side of said flattened tubular sleeve, said extensions extendingacross the ends of said folds and the unifolded sides at the open end ofsaid bag to lie against the outer surface of said unfolded sides, thewalls of said sleeve be.-

ing bonded to the walls of the folds in which it is positioned and saidextensions being bondedsaid opposed outwardly extending reentrant folds,

integral extensions on each side of said tubular member extending acrossthe ends of the walls of said reentrant folds and lying against theunfolded sides of saidbag, said flat tubular member being bonded to theinside of the walls of the reentrant folds in which it is positioned andsaid extensions being bonded to the-outside of the unfolded sides ofsaid big thereby locking" the walls of the remainder of said reentrantfolds to each other and constituting the-sole means for preventing theirexpansion. I

11. In a suction cleaner, an open ended paper filter bag folded alongits length'to form three opposed pairs of outwardly extending reentrantfolds lying between two unfolded sides at each edgethereof whereby itcan beflattened with the walls of the reentrant folds superimposed uponeach other and upon the unfolded sides of. the 1 bag, a flattened tubehaving its edges. extending into one pair of opposed reentrant folds,integral extensions on both sides of said flattened tube extendingacross the ends of the Walls of said reentrant folds and lying againstthe unfolded sides of said bag, said flattened tube being secured to thewalls of said reentrant folds; in which, it is positioned and saidextension being secured to the unfolded sides of said bag, said tube andextensions forming sole connection between the walls of said reentrantfolds.

12. In a suction cleaner, an open ended paper filter bag folded alongits length to form three outwardly extending reentrant folds. and twoin-. wardly extending reentrant folds on' each side so that the bag willlie flat with the walls of. said: reentrant folds superimposed, acombined dirt trap and reenforcing member associated with the Opel-fend;of said bag; said member having: anattened tubular portion positioned:between the Walls oflone pair of said outwardly extending re: entrantfolds and integral extensions formed on one end of both sides of saidflattened tubular portion, said extensions being folded over the ends ofthe walls of said reentrant folds so as to lie against the unfoldedsides of' said bag and means for securing said tubular portion to theinner sides of the Walls of the reentrant folds in which it ispositioned and for securing said extensions to the unfolded sides ofsaid bag, said folded over extensions forming the sole securing meansbetween the walls of said reentrant folds.

13. In a suction cleaner, an open ended filter bag folded along two ofits opposed sides to form a plurality of opposed mating outwardlyextending accordion-like folds and opposed fiat unfolded sides with theouter apices of said folds extending along the edges of the unfoldedsides with the walls forming said folds being superposed upon each otherand upon the walls forming the unfolded sides of said bag at each edgethereof, a flattened tubular sleeve positioned within one pair of saidopposed mating folds with its edges extending to the apices thereof, theremainder of said folds remaining unoccupied, ex-

10 tensions integral with each side of said flattened. sleeve,v saidextensions extending across the: ends of the walls of both the occupiedandunoccupied folds and lying: against the outer surface of the wallsforming the unfolded side of, said bag, thesides of said sleeve beingbonded to the inside of thewalls'of thefolds in which it is positioned?and said: extensionsbeing bonded to the unfolded sides; of saidbag, saidsleeve and extensions form.-

ing the sole means for holding the unoccupied foldsfromexpanding.

14:. Ina suction cleaner, an. open ended filter bag folded. along. twoof. its opposed sides to form three.- opposed mating outwardly extendingac cordion1ike folds-and opposed flat unfolded sides with the outerapices of said folds extending. along the edges of the unfolded sidesandwith. the walls of said folds being superimposed upon each other andupon the fiat unfolded sides at.

each edge of said bag, a flattened tubular mouth forming sleevepositioned withinthe central: pair, of said opposed folds with itsedges' extending. to the apices of said central folds, extensions inte--gral with each side of said sleeve, said extensions extending across theends of the foldson opposite sides of said central folds andlyingagainst the outer surface of the unfolded sides of said bag, saidsleeve and extensions being impregnated with a heat scalable cement,said sleeve being heat sealed to the-inner surface of. said cen tralfolds and said extensions being heat sealed to the outer surface of theunfolded sides of said: bag.

15. In a suction cleaner, an open ended filter bag folded along two ofits opposed sides to form a plurality of opposed mating outwardlyextending accordion-like folds and opposed flat unfolded sides with the:outer apices of said folds extending. along the edges of. the unfoldedsides and with the walls of said folds. being, superposed upon eachother and upon the Walls fomring the unfolded sides ofv said bag. at.each edgethereof, the material of said folds andflat sides being cut toform a shallow reentrant V-shaped open end for said bag,-a flattenedmouth formingsleeve positioned within one pair. of saidopposed foldswithits edges extending to the outer apicesthereof, integral. extensionson each side of said sleeve, said. extensions being: folded across theends of saidfolds to lie against the outer surface of said fiat unfoldedsides, a locating notch formed. centrally in one side of said sleeve,the inward edge of said notch being: located substane tially at the apexof the V-shaped. open end of. said bag, said. sleeve being secured totheinner surface of the folds in which it. is positioned andsaid. extensionbeing secured to the outer sidesof said fiat unfolded sides.

16. In a suction cleaner according to claim' 15 in which the fold linesbetween the sides of said sleeve and said extensions form an outwardlyextending V-shaped edge on one side of said sleeve and a reentrant edgeon the other side thereof with said notch being located at the apex ofsaid reentrant edge.

17. A blank for forming a dirt trap and reenforcement for a filter bagmouth comprising, a substantially rectangular central panel, a sidepanel hinged to each side edge of said central panel, the combinedwidths of said side panels being greater than the width of said centralpanel, a central extension hinged to the central portion of one end ofsaid central panel on a fold line normal to the side edges of saidcentral panel, a side extension hinged to one end of each side panel ondiagonal hinge lines sloping toward the hinge line for said centralextension, a flap hinged to the inner edge of each of said sideextensions on fold lines forming continuations of the fold lines betweensaid central and side panels so as to overlie said central panel, saidflaps being separated from said central extension by a diagonal cut, anda locking tab hinged to the lower edge of each flap on hinge linesforming a continuation of the hinge lines between said side panels andside extensions, said locking tabs being cut from the material of saidcentral panel.

18. A blank according to claim 17 in which a circular opening is cutcentrally in said central panel and extension on the fold line betweenthem to form a locating notch when the blank is folded about a bagmouth.

19. A blank for forming a dirt trap and reenforcement for attachment toa filter bag mouth comprising, a central substantially rectangularpanel, a side panel hinged to each lateral edge of said central panel,the combined widths of said side panels being greater than the width ofsaid central panel so as to overlap when folded over upon said centralpanel, a pair of extensions hinged to one end of said central panel onsloping hinge lines meeting at an outwardly extending apex centrally ofsaid central panel, said central extensions being separated by a outline extending diagonally from said apex and a side extension hinged toeach side panel on hinge lines forming extensions of the hinge linesbetween said central panel and central extensions.

' 20. A blank according to claim 19 including locating openings cut ineach of said side panels and extensions on their fold lines adjacenttheir free edges so as to mate when said side panels are folded uponsaid central panels.

21. In a filter bag, a flattened trap forming sleeve positioned in thecentral folds of an open end flattened bag of filter paper havingaccordion-like folds extending inwardly from its opposite edges, a firstreenforcing extension of less width than said flattened sleeve centrallyattached to one side of said sleeve and extending across the folds onone side of the bag and lying against one of its fiat sides, second andthird reenforcing extensions attached to the other side of said sleeveon diagonal fold lines meeting centrally of said other side of saidsleeve to form an outwardly extending apex, said second and thirdextensions extending across the ends of the folds on the other side ofthe bag and lying against the other fiat side thereof, a reenforcingfiap attached to the outer edges of said second and third reenforcingextensions and extending across the edges of the bag at its open end andlying against the first mentioned flat side of the bag at opposite endsof said first reenforcing extension, and a locking tab attached to eachflap and extending across the ends of the folds on the first mentionedside of the bag and lying against the interior surface of the centralfolds of the bag, said sleeve, extension, flaps and tabs being bonded tothe surface of the bag walls with which they are in contact.

22. In a filter bag according to claim 21 in which the open end of saidbag is cut to form a shallow reentrant V-shaped end and said firstreenforcing extension and the first mentioned side of said sleeve areformed with an inwardly extending positioning notch having its inneredge positioned at the apex of said V-shaped end.

23. In a filter bag, a flattened trap forming sleeve positioned in thecentral folds of an open ended flattened bag of filter paper havingaccordion-like folds extending inwardly from its opposite edges, firstand second reenforcing extensions attached to one side of said flattenedsleeve on outwardly inclined fold lines meeting centrally of said oneside to form an outwardly extending apex, said first and secondextensions extending across the ends of the folds on one side of the bagand lying against one fiat side thereof adjacent said open end, thirdand fourth reenforcing extensions attached to the other side of saidsleeve on fold lines inclined in the opposite direction from the firstmentioned fold lines and meeting at a reentrant apex centrally of saidother side of said sleeve, said third and fourth extensions extendingacross the folds on the other side of the bag and lying against theother fiat side thereof adjacent its open end, said sleeve andextensions being bonded to the surfaces of the walls of said bag withwhich they are in contact.

24. In a filter bag according to claim 23 in which the open end of saidbag is cut to form a shallow reentrant V-shaped end and said third andfourth extensions and the second mentioned side of said sleeve areformed with an inwardly extending positioning notch having its inneredge positioned at the apex of said V-shaped end.

WILLIAM H. WOESSNER.

' References Cited in the file of this patent UNITED STATES PATENTSNumber Name Date 2,444,762 Waters July 6, 1948 2,488,038 Sharkey Nov.15. 1949 2,564,845 Holt Aug. 21, 1951 2,566,275 White Aug. 28, 1951

